Sleep disorders are increasingly recognized to be common in the American population and to have important adverse consequences, not only on behavior with an increased risk of crashes but also on the cardiovascular system. Thus, sleep disorders are a major public health problem. This application is for renewal of a postdoctoral research training program for sleep research and research in sleep disorders at the University of Pennsylvania. The overall goals of the program are to train a cadre of independent investigators on these topics with a particular focus on physician-scientists. The training program has three distinct tracks: a) basic research, b) translational research, and c) patient-oriented research. Each track combines didactic training with an intense research experience working with a mentor(s). The program utilizes established Masters Degrees at the University of Pennsylvania to amplify what is provided by this particular program. The relevant Masters degrees are the Masters in Translational Research (Track 2) and the Masters in Clinical Epidemiology (Track 3). The program utilizes the infrastructure for research in sleep and its disorders that has been developed at the University of Pennsylvania by the interdisciplinary Center for Sleep and Circadian Neurobiology. This infrastructure is for both basic and clinical research and includes a dedicated 4-bedroom sleep research facility for studies in humans, including patients with specific sleep disorders. The program utilizes a group mentorship model and a mentorship committee is established for each trainee. Trainees are given specific training not only in sleep research but also in survival skills, including how to write grants. Career counseling is provide to each trainee and many of the trainees go on to successful academic careers as independent investigators. The strengths of the program include: a) a stable, dedicated leadership; b) a large group of productive research-oriented faculty who work in a very collaborative fashion; c) strong institutional support; and d) major research funding for faculty to pursue research. (End of Abstract)